LENS DYEING METHOD AND LENS DYEING APARATUS: DYEING LENSES TO GIVE A CONTINUOUS COLOR DENSITY GRADIENT

摘要

A dyeing method for dyeing plastic lenses or the like employed as lenses for eye glasses and exhibiting excellent dyeability. The lens is dipped into a dyeing solution while being moved by a combination of a small-amplitude short-cycle time up and down reciprocating motion superimposed on a large-amplitude long-cycle time up and down reciprocating motion. The lens is minutely oscillated according to the small-amplitude short-cycle time up and down reciprocating motion while being periodically moved up and down in the dyeing solution according to the large-amplitude long-cycle time up and down reciprocating motion. The lowest position of the lens obtained by the large-amplitude long-cycle time up and down reciprocating motion is raised gradually. Also disclosed is a dyeing apparatus which is used to carry out that dyeing method.